This diagram shows the spectrum of Regulus and similar stars. A spectrum spreads a star’s light into its individual wavelengths or colors. Dark lines in the spectrum indicate the presence of chemical elements in the star. Each element produces a unique pattern of lines, allowing astronomers to deduce its composition. In addition, a spectrum reveals a star’s motion, temperature, and whether the star has unseen companion stars. This illustration was drawn by Angelo Secchi, who created a classification system for stars, in the 1880s.
Find out more in our radio program entitled Moon and Regulus.